Electric switch



March 10, 1942.. E. ArwlLLIAMS, JR, ET AL 2,275 1 I ELECTRIC SWITCH Filed Aug. 2, 1940 INSU ON Theh'- Att yey' Patented Mar. 10, 1942 V ELECTRIC SWITCH Edwin A. Williams, Jr., Lansdowne, Carl L. Schuck, Philadelphia, and Gerald P. Clute, Drexel Hill, Pa., assignors to General Electric Company, a-corporation of New York Application August 2, 1940, Serial No. 349,846

18 Claims.

The present invention relates to electric switches, with reference more particularly to improvements in construction of switches of the kind employable as disconnecting devices and having a switching element or blade pivoted for swinging movement to and from a closed position between relatively stationary terminal contacts.

It is common to provide some means for limiting or arresting the opening swinging movement of the switching element in such devices, and for holding the switching element in a predetermined position such as, for example, a position in which the switching element is readily engageable' by a switch hook or other bperatlng tool for removal of the element from the switch support. Fixed solid'stops are used for this purpose in some forms of disconnecting switch devices. Resilient buffers in the form of spring strips, also have been proposed for the purpose. However, in any case where a switching element of considerable size or weight is employed, there is danger of breakage of the switching element or its support if the switching element is allowed to swing freely into engagement with a solid stop. The danger of breakage of the switching element by engagement with a solid stop, likewise is present in the case of a disconnecting device employing a fused switching element wherein the fuse holder includes a casing constructed oi glass, porcelain, or other frangible material. The spring strip form of resilient buffer is unsatisfactory for the reason, among others, thatit is difiicult to provide a spring strip of practical dimensions, which has the desired resiliency and at the same time is capable of effectively arresting and accurately positioning a large or heavy switching element.

It'is one of the objects of-the' present invention to provide, in a disconnecting switch support, a resilient buffer mechanism which is capable of arresting and maintaining a switching element accurately in a predetermined position, and of absorbing a considerable shock of impact without damage to the switching element or the switch support. v

In the case of a switching element pivotally mounted so as to be readily removable from its support, it has been found that swinging of the switching element into engagement with a stop or buffer near one end of the element, may set up forces which tend to cause disengagement of the switching element from its support. The present invention therefore has for another object, the provision of improved latching mechanism for preventing disengagement of a switchwith a switching'element pivoted on the support,

when the switching element is in closed position, and of absorbing the shock of impact of the switching element against the bufier mechanism when the switching element swings to open position.

Other objects and the details of that which we consider to be novel and our invention, will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawing wherein:

Fig. 1 shows, in side elevation, an exemplary form of disconnecting switch device embodying our invention;

Fig. 2 is an enlarged side elevation, partially in section, showing details of the hinge, contact, butter, and latch mechanism at the lower end of the device of Fig. 1;

Fig. 3 is front elevation, partially in section, of the mechanism shown in Fig. 2;

Fig. 4 is a sectional plan view along the line 4-4 of Fig. 2;

Fig. 5 is an exploded view showing, in per- I Fig. 8 shows the mechanism of Fig. 7 with the switching element in an open position.

As will be evident from the ensuing description, various features of the present invention are subject to modification and are suitable for employment in other forms of switch devices. Hence the embodiment shown in the drawing is for purposes of illustration only. In this embodiment the fuse support includes two insulators, l0 and I I, disposed in spaced relationship and bolted or otherwise secured at one end to a suitable base. 7

I2. 011' the outer end of the upper insulator, Hi, there is supported a terminal and. contact assembly including a terminal plate |3 having an upwardly projecting extension to which electric line conductors or leads may besecured by clamping devices I4. A contact I5 is rotatably supported on a pin 5 carried by a bracket mounted on terminal plate l3. One or more springs serve to bias contact |5 for rotation in a clockwise direction, as viewed in the drawing, and an adjustable stop screw 2| is provided on the lower end of the contact for limiting its rotation. A flexible braided conductor 22 insures good electric connection between the contact and terminal plate l3. The contact has two outwardly projecting arms 23, one of which may be seen in the drawing, for receiving therebetween and engaging the upper end of a switching element. An outwardly projecting finger 24 also is provided on the contact for a purpose hereinafter described.

On the outer end of lower insulator I, there is mounted a terminal member 25 which, similarly to terminal plate l3, has an extension to which line conductors or leads may be secured by clamping devices H. The upper partof terminal member 25 is adapted to serve as a hinge support and has two integrally formed bracket arms 26 disposed in horizontally spaced relationship,

and each of which bracket arms has a hook portion designed to provide a trunnion seat 21, The bracket arms serve to support a contact member 30 in accordance with one feature of the present invention. This contact member is generally rectangular and hollow, and is open at the rear as will be seen best from Fig." 5. On opposite sides of the contact member are lugs 3| which engage bearing slots 32, adjacent the tops of the bracket arms, for slidably supporting the contact member between the bracket arms. Hook shaped stops 33 serve to maintain lugs 3| in slots 32 and also to limit outward sliding of the contact member. outwardly by coiled springs 34 engaged at their outer ends with pins 35 on the inside of the contact member. Although two such springs are employed in the exemplary embodiment illustrated, it will of course be understood that one, or more than two, may be employed if desired. A flexible braided conductor 36, secured at one end to terminal member 25 by a bolt 31 and secured at the other end to contact member 30 by a bolt 38, is provided for insuring good electric connection between the terminal member and contact member.

A buffer member 40 is rotatably supported, intermediate its ends, between bracket arms 26. The support for the buffer member comprises a pivot pin 4| which extends through openings 42 in the opposite sides of the buffer member. The opposite ends of pin 4| are engaged with openings 43 formed respectively in bracket arms 25 at points slightly below and to the rear of trunnion seats 21. Pin 4|- is retained in openings 42 by cotter pins 44 or other suitable means. Buffer member 40 is generally L-shaped and is arranged so that one arm thereof projects forwardly and downwardly so as to be in opposed spaced relation to the bottom of a switching element supported by bracket arms 25 in a manner later described. The other arm of the buffer member projects upwardly between the bracket arms and extends behind contact member 30. At the upper end of the buffer member are pins 45 which support the inner ends of springs 34,

The contaot member is biased Thus the springs arecompressed between the buffer member and the contact member, and serve .to bias the contact member outwardly while opposing rotation of the buffer member in a clockwise direction, as viewed in the drawing. Counter-clockwise rotation of the buffer member is limited by engagement thereof with terminal member 25, so that'the forwardly projecting arm of the buffer member is maintained in the position shown in Figs. 1 and 2.

The present invention may be embodied to advantage in switch supports forthe mounting of various forms of switching elements or blades, and it is not intended therefore that the invention be limited to any one particular form of switching element or blade. However, the illustrated exemplary switch support is especially suited for the mounting of switching elements embodying fuse devices having casings constructed of glass, porcelain, or other frangible material. Such a fuse device is indicated at 50 on the drawing. This fuse device may, for example, be of the form shown in U. S. Patent No. 2,188,816, issued January 30, 1940, in the name of W. K. Rankin, and assigned to the same assignee as the present invention. Fuse devices of the form shown in the Rankin patent, are of considerable size and weight, particularly when designed for high current interrupting ratings. They include a fusible element, and insulating support therefor, embedded in a body of sand or granular quartz which is contained in a tubular glass casing such as that indicated at 5| in the drawing. Opposite ends of the glass casing are closed by metallic terminal ferrules 52 which serve for connection of the fuse unit in an electric circuit.

For mounting the fuse holder, comprising casing 5| and ferrules 52, on the previously described switch support, appropriate fittings are applied on the upper and lower ends, respectively, of the fuse holder. The lower fitting comprises a metallic ring 53 clamped on the lower terminal ferrule 52 by means of bolt 54. This ring has rearwardly projecting spaced arms 55, each of which has an integrally formed trunnion 55 for engagement with one of the trunnion seats 21 of the hinge support. When trunnions 55 are engaged with the trunnion seats in the manner shown in Figs. 1 and 2, arms 55 are disposed between bracket arms 26 and respectively on opposite sides of buffer member 40, as will be seen best from Fig, 4. Ring 53 also has two downwardly extending latching parts or projections 51 disposed respectively on opposite sides of the ring, and spaced forwardly from trunnions 56 so as to be just outside of the hook portions of bracket arms 26. If desired, trunnions 56 and projections 51 may comprise elements of a hinge part fixedly mounted on the fuse holder. Also, trunnions 56, instead of being formed integrally with ring 53, may comprise ends of a hinge pin extending between and projecting on opposite sides of arms 55. It will be noted that the axis of the trunnions is offset a substantial distance laterally from the longitudinal axis of the fuse holder so that the weight of the fuse holder tends to cause rotation of the switching element to open position when the trunnions are engaged with the trunnion seats.

The fitting on the upper end of the fuse holder comprisesa metallic contact ring 60 clamped on upper terminal ferrule 52 by means of bolt 6|. This contact ring has a. rounded or semi-spherical surface 32 for engagement by complementary aerosol.

surfaces on the arms 23 of'upper pivoted contact E5. The forward portion of ring 80 has two upwardly projecting lugs 88, one of which may be seen in the drawing, which serve to support a pivot pin 86 upon which a combined handle and latch releasing member 85 is rotatably mounted. Member 66 has a rearwardly projecting finger 86 arranged to extend under finger 24 on contact l when the switch element is in closed position. The forward portion of member 65 is in the form of an oval ring 61 adapted to provide an operating eye for engagement by a common form of switch hools or operating tool. 0n the top oi member 65 are two upwardly projecting cylindrical elements and 1| disposed in spacedaxial alinement and adapted to provide a socket for receiving one end of the insulating pole 12 of a switch hook in the manner indicated in Fig. 6. Element 1| is open on one side, as indicated at 13, to provide for passage of hook projection H when the end of the switch hook is inserted into the socket in the manner later described.

With trunnions 56 engaged with trunnion seats 21, the switching element may be swung into closed position, connected between terminals l3 and as shown in Fig. 1, and is latched in such position by engagement of arms 23 of upper contact IS with the contact ring 60 on the upper end oi the fuse holder. Under these conditions,

I springs 20 maintain firm pressure engagement between contact arms 23 and contact ring W, while springs 35 maintain firm pressure engagement between contact member and this lower terminal ferrule 52. When it is desired to swing the switching element to an open position, the

hoolr projection 14 of an operating tool, such as that partially shown in Fig. 6, is engaged with eye ill, and a downward pull is exerted on the operating tool so as to rotate member 66 in a clockwise direction as viewed in the drawing.

This causes finger B6 to engage finger 2d and lift contact l5 so as to free the upper end of the fuse holder whereupon the switching element may be swung to an open position. If the switch hook is maintained in engagement with eye 61, the switching element may be rotated relatively slowly to the open position wherein ring 53 at the bottom of the fuse holder engages the forwardly projecting arm of buffer 40, as shown in.

However, if the switch the broken lines in Fig. I. hook accidentally should become disengaged from eye 87, the switching element will swing freely and with considerable force against buffer 40. Under these circumstances, springs effectively absorb the shock 01 impact and prevent damage to the switching element and the switch support.

Trunnions 56 are prevented from jumping out of trunnion seats El when the switching element swings into engagement with the buffer, by reason of the fact that projections 51 swing into partially underlying relation to the hook portions of brackets 26 so as to latch the trunnions in the trunnion seats.

When the switching element is moved out of closed position, lugs 3! of contact it slide into engagement with stops 33 so that a solid back.- ing is provided for the forward ends of springs 38. Under these conditions the springs are effective to oppose any considerable clockwise rotation of buffer member 40 and serve to position the butter member accurately for holding the switching element in the desired open position as indicated by the broken lines in Fig. 1 and by the view of the upper end of the switching element in Fig. 6. When theswitching element is in the '16 to a vertical position between elements 10 and .1l. This eilectively locks the switch hook in engagement with handle 85 so that the switching element may be removed i'rom its support without danger of the switching element dropping off of the switch hook. Removal of the switching element from its support is eflected by swinging the switching element slightly upwardly from its extreme open position so as to bring projections 51 into positions which will permit ready'diseneasement or trunnions 56 from trunnion seats 2'1.

With the switching element removed from the support, fittings or rings 53 and 60 may be removed from the holder or a blown fuse unit and applied to the holder 01 a new fuse unit, which then may be installed on the support by following the above described operations in the reverse order.

In the modification shown in Figs. 7 and 8, projections 51 are omitted from ring 53 and there is provided. instead, a butler member 15 which has latching bosses or projections 16 formed thereon intermediate the upper end 0! the buffer member and its pivotal support 4|. Otherwise. the construction and arrangement of the various parts is substantially the same as previously described in connection with the embodiment of Fig. 1. When the switching element is in the closed position, partially shown in Fig. '7, projections or bosses 16 are disposed in retracted positions. When the switching element swings to the open position, partially shown in Fig. 8, and engages buiier 15, the resultant rotation of the buffer in a clockwise direction causes projections 18 to swing into positions overlying portions of the hinge part which includes trunnions 56. Thus the trunnions are blocked against disengagement from the trunnion seats due to such forces as might be set up by swinging of the switching element into engagement with the buffer. For intentional disengagement of the trun removal of the trunnions. from the trunnion seats.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric switch, a supporting structure having spaced terminals, :1 switching element pivoted on said structure so as to be swingable to and from closed position between said terminals. a buffer pivoted on said structure and arranged for engagement by said switching element so as to arrest the opening movement of the s r/itching element and hold the latter in a predetermined open position. and spring means arranged to act on said buffer in a manner to resist displacement of the buffer, said spring means being operative to absorb the shock of impact of said switching element against the buffer.

2. In an electric switch, a supporting structure having spaced terminals, a switching element disposed in a closed position between said terminals and pivoted adjacent one end on said The switch hook. pole then is rotated in a manner to swing projection supporting said structure so as to be swingable to an open position, a buffer member pivoted on said structure and extending in opposed spaced relation to said one end of the switching element-so as to be engageable by said one end of the switching element as the latter swings to open position, and shock absorbing means arranged to oppose displacement of, said buffer member when the switching element swings into engagement with said member, said member and shock absorbing means being operative to arrest hing element in a predetermined open position.

8. In an electric switch, a supporting struc ture having spaced upper and lower terminals, a switching element extending in a generally up right position connected between said terminals, said element being pivoted on said structure adjacent its lower end so as to be swlngable to an open position, the axis oi pivoting of said element being offset a substantial distance laterally from the longitudinal axis of said element, a buffer member pivoted on said structure and extending below and in spaced relation to the lower end 01 said switching element so as to be engageable by the bottom of said element as the latter swings to open position, and spring means arranged to oppose displacement oi. said buffer member and operative to absorb the shock of impact of said switching elementagainst the buffer member.

4. In an electric switch including a support-' ing structure having switching element pivoted adjacent one end on said structure for swinging movement into and out of closed position between said terminals; a lever-like member pivoted on said structure adjacent said one end of said switching element for rotation about an axis substantially parallel with the pivotal axis of the switching element,

said member being pivoted intermediate its ends,

one end of said member being arranged for engagement by said switching element to arrest opening movement of said element when the latter reaches a predetermined open position,

and shock-absorbing spring means arranged to act-on the other end of said lever-like member in a manner to oppose rotation of said member due to'cngagement of said switching element with said member.

5. In an electric switch, relatively stationary spaced terminals, a switching element for conn'ection between said terminals, hinge means element for swinging movement into and out of closed position between said terminals, said hinge means including a pair of spaced terminals, and a r hinge bracket arms disposed in spaced relation ship and pivot means engaged with said bracket arms, a bufier member rotatably supported on pivot means engaged with said bracket arms, said bufler member arranged for engagement by said switching element so as to arrest opening movement of the switching element, and coiled spring means arranged to act on said bufle'r member in a. manner to absorb the shock of impact of said switching element against the bufier member and to oppose displacement of the'bufler member by the switching element.

6.- In an electric switch, relatively stationary spaced terminal means, a switching element for cooperation therewith, hinge means supporting said element for swinging movement into and out of connected position, said hinge means including a pair of hinge bracket arms disposed in spaced relationship, said switching element being supported by pivot means engaged with corona said bracket arms, a contact member forming part of one of said terminal means, said contact member being disposed generally between said bracket arms and being slidably supported on the bracket arms, and spring means arranged to force said contact member into pressure en gagement with cooperative contact means on said switching element.

7. In an electric switch, ture having spaced terminal in element connected between soi ms and pivoted for swinging movement to an open position, one of said terminal means including a movable contact member engageable with cooperative contact means on said switching element, 9; buffer member movably mounted on said supporting structure and arranged for en gagement with said switching element to arrest opening movementoi said element, and resilient means arranged to serve the double function of forcing said contact member into pressure engagement with said contact means when the switching element is in closed position and of absorbing the shock of engagement of the switching element with the butter member when the switching element swings to open position.

8. In an electric switch, a supporting structure having spaced terminal means, a switching element disposed in a closed position between said terminal means and pivoted adjacent one end for swinging movement to an open position, a movable contact member forming part of one of said terminal means and arranged for engagement with cooperative contact means on said switching element, a buffer member pivoted on'said structure adjacent said one end of the switching element and engageable with the latter'for arresting the opening movement oi. the switching element, and spring means arranged to force said movable contact member into pressure engagement with said contact means when the switching element is in closed position, the same said spring means being arranged to absorb the shock of impact of said switching element against-the bufler member when the switch ing element swings to open position 7 9. In an electric switch, a supporting structure, a switching element pivoted thereon, spaced terminal means carried by said structure for cooperation with said switching element and including a movable contact member arranged tor engagement with contact means on the switching element, a butler member pivoted on said structure and arranged for engagement by said switching element to arrest the opening movement of the latter, and spring means acting between said contact member and said buffer memher, said spring means maintaining said contact member in pressure engagement with said contact means when the switching element is in closed position, said spring means also being operative to oppose displacement of said bufler member when said switching element swings into engagement with the buffer member.

10. In an electric switch,.a supporting structure, a switching element pivoted thereon, terminal means on said structure including a movaable contact member engageable with contact means on said switching element when the latter is in one position, a bullet member pivoted intermediate its ends on'said structure, one arm of said butler member being arranged for engagement by said switching element to arrest the switching element in a second position when said element swings from its first mentioned position,

and one or more springs compressed between closed position, a buirer member said contact member and the other arm of said bufler member so as to maintain the contact member in pressure engagement with said contact means on the switching element when the latter is in its said first mentioned position. said spring or springs also being operative to absorb the shock or impact between said bufier member and switching element when the latter swings to its said second position.

11. In an electric switch, a hinge support including a pair of bracket arms disposed in spaced relationship, a switching element swingably supported adjacent one end by pivot means engaged with said bracket arms, terminal means for cooperation with said switching element'including a contact member movably mounted on said hinge support, a front portion of which contact member is arranged to engage said switch element when the latter is in one position, a leverlike member rotatably supported intermediate its ends by pivot means engaged with said bracket arms, oneend of said lever-like member being arranged to serve as a buffer for arresting said switching element in a predetermined second position when the switching element swings from its first mentioned position, the other end of said lever-like member extending behind said contact member, and one or more springs compressed between said other arm of the lever-like member and the rear of said contact member.

12. In an electric switch, stationary terminal means, a switching element cooperative therewith, a stationary hinge support including spaced bracket arms having trunnion seats openadiacent the top, the lower end of said switching element including a hinge part having trunnions removably engaged with said seats and pivotally supporting the switching element for swinging movement to open position relative to said terminal means, a movable contact member forming part of said terminal means and engageable with said switching element when the latter is in ported intermediate its ends on pivot means engaged with said bracket arms, the lower end of hinge part in'a manner to prevent disengagement of said trunnions from said trunnion seats, said part of the bufler member being swung to said overlying position upon engagement of said switching element with the buifer member,

14. In an electric switch, relatively stationary mounted adjacent said one end of said element and operative to limit the opening swinging movement of said element, and latch mcans'on said buiIer member arranged for movement to a blocking position relative to said one end of the switching element in a manner to prevent dis-- engagement of said trunnions from said open trunnion seats, said latch means being moved to said blocking position upon engagement and movement oi. said buffer member by said switching element.

15. In an electric switch, relatively stationary terminal means, a switching element removably disposed in a closed position relative to said ter-= minal means, hinge means on one end of said switching element and detachably engaged with a relatively stationary hinge support so as pivotally to support said switching element for swinging movement to an open position, a buffer member movably supported adjacent said one end of the switching element so as to be engagemeans on said buffer member, which said latch means is arranged to move into a position to prevent disengagement of said hinge means from rotatably supsaid bufier member extending below and in spaced relation to the lower end of said switching element for limiting the opening swinging movement of said element, shock absorbing spring means compressed between said contact member and the upper end of said buffer member for forcing the contact member into pressure engagement with the switching element, and latch means on said buffer member arranged to rotate into overlying relation to a portion of said hinge part when said switching element swings into engagement with the buifer member, so as thereby to prevent disengagement of said trunnions from said trunnion seats.

13. In an electric switch, relatively stationaryterminal means, a switching element swingable to and from closed position relative to said terminal means, a support for said element having trunnion seats open adjacent the top, said element having a hinge part including trunnions adjacent its lower end, which said trunnions are removably engaged'with said trunnion seats to said hinge support when the switching element swings into engagement with the buffer member, 16. In an electric switch, a support having terminal means thereon, a switching element swingable to and from closed position relative to said terminal means, said element being pivotally supported adjacent one end by cooperative hinge parts respectively on said element and on said support, one of which hinge parts is de tachably and pivotally engaged with an open socket portion of the other hinge part, a buffer t member pivoted on said support and operative to limit opening movement of said switching element, and a latch part on said buffer member arranged to move into a position to block said one hinge part so as to prevent disengagement-thereof from said open socket portion of said other hinge part, said latch part being moved into said blocking position upon engagement and movement of said bufier member by said switching element.

17. In an electric switch relatively stationary terminal means, a movable switching element, hinge means pivotally supporting said switching element for swinging movement to and from closed position relative to said terminal means, said hinge means including spaced bracket arms each having an open trunnion seat, said switching element having trunnions adjacent one end thereof and removably engaged with said trunnion seats, a buffer member adjacent said one end of the switching element for limiting the opening swinging movement of the switching element, and latch parts on said switching element adjacent said one end thereof, which said latch parts are arranged to swing into position for cooperation with portions of said bracket arms in a manner to prevent disengagement of said trunsaid hinge means including spaced bracket arms having heal; :"tions providing trunnion 5s open aches-e11 a top, said switohing element having tmnhions adjacent its lower end removably engaged with said trunnion seats, a buffer member adjacent the lower end of the switching element for limiting the opening swinging movement, and latch parts on said switching element acljacent said trunnions, which said latch parts are swingable into positions at least partially un deriylng said hook portions of the bracket arms so as to prevent disengagement of said trunnions from said trunnion seats when the switching e1ement swings into engagement with said buffer member.

EDW'H? A, WiilfiiAt/LIS, JR. CARL SCI-Fe GERALD P. CLU CL". 

